Integrated Geoscience Studies for Volcanic Hazard Mitigation of Mt. Agung, Bali, Indonesia
Abstract
Mt. Agung is currently erupting on the island of Bali in the Indonesian archipelago. In late November 2017, it erupted and generated dense gray ash plumes rising as high as 4 km above the crater rim. More than 100,000 people were initially evacuated, two international airports (Lombok and Ngurah Rai) were temporarily closed and caused economic losses of about ~800 million USD. The eruption activities of Agung continue in 2018 and 2019. In late 2018, we deployed a network of seismic (Trillium Compact 120s) and geodetic instruments at Agung as part of a USAID funded collaborative project. Using the data collected, we are employing seismological, geodetic/Global Positioning System (GPS) and geomechanical methods to study the subsurface structure of Agung and the dynamics of the eruption. The seismological methods include: (i) body wave seismic tomography, (ii) surface wave tomography using ambient noise data, (iii) shear-wave splitting analysis, and (iv) anisotropy analysis. Hypocenter determination is being performed using traditional and double-difference techniques. For the geodetic study, we are conducting a GPS campaign at Mt. Agung for several months. The GPS data from this campaign will be used jointly with data available from recent GPS observations/campaign and continuous networks available in the study area. We aim to identify active structures that accommodate the magma migration in the shallow reservoir using the surface deformation data. In addition, a modeling of stress transfer will also be conducted. This modeling has great value for understanding the potential earthquake interaction and the stress perturbation. Finally, the resulting models based on the seismological, geodetic/GPS and geomechanical data processing will be integrated for tectonic interpretation. We expect that this integrated data will allow us to improve hazard assessment and risk mitigation at Mt. Agung. Our preliminary results, e.g., 2-D tomographic maps obtained from the inversion of the group velocity of Rayleigh wave depict clearly a prominent feature, i.e., a strong low velocity anomaly underlying the volcanic complex between Mt. Agung and Mt. Batur. This anomaly may be related to a magma intrusion between the two mountains, which has induced seismicity as well as ground deformation.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.V51J0220W
- Keywords:
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- 8414 Eruption mechanisms and flow emplacement;
- VOLCANOLOGY;
- 8419 Volcano monitoring;
- VOLCANOLOGY;
- 8485 Remote sensing of volcanoes;
- VOLCANOLOGY;
- 8494 Instruments and techniques;
- VOLCANOLOGY